1. Technical Field
The present invention is generally directed to the computer database technical field, and more specifically to the field of distributed client/server database applications.
2. Description of the Related Art
Object Oriented programming has become the standard paradigm by which software is developed. As part of this paradigm, an object's state is often persisted. As software systems grow, the number of objects being persisted grows accordingly. In a complex software system, the object model contains many associations between the objects. These associations are also persisted. For example, an object model may contain over 90 classes and 180 associations that are stored in a persistence layer (which is usually a database).
In a distributed client/server application, the client needs to query the object model, which is located on the server, to obtain the persisted states of the objects. Under such current approaches as the Distributed Component Object Model (DCOM) and Common Object Request Broker Architecture (CORBA) model, the client application requests and receives a single object or a collection of like objects. To navigate a specific path through the object model, the client application must retrieve each set of objects along the path to get to the next set of objects in the path.
For example in a company information database application, the client application may want to find all company divisions that have employees who make more than $17,000. These approaches obtain that information by retrieving each of the division objects (10 objects transferred to the client application), loop through each one and get its departments (100 objects transferred to the client application), and loop through each one getting its list of employees (1000 objects transferred to the client application). From these 1000 objects transferred, only one division may actually have been needed by the client application. This is an inefficient process that requires the transmission of significant amounts of potentially irrelevant information across the network.